A vertical probe card is generally used in testing of dies of flip chip packages, and in the parallel testing of multi dies surrounding a pad. As shown in FIG. 1, a probe head of a vertical probe card is disposed under a circuit board (not shown), so that the top end and the bottom end thereof are electrically connect to an electronic device under test and the circuit board, respectively. The probe head includes a top guide plate 1, a bottom guide plate 2, and a plurality of probe pins 3. The probe pins 3 are penetrated through the top guide plate 1 and the bottom guide plate 2, so as to be supported and positioned. Due to the densely disposed electronic devices under test, the probe pins 3 are thereby arranged tightly. During the testing process, the tips 3a of the probe pins 3 are aligned with and contacted to a plurality of electronic devices under test 4, thus are electrically connecting to the electronic devices 4.
In a known conventional vertical probe card, the top guide plate and the bottom guide plate are made of plastic material. The thermal expansion coefficient of the plastic material is much larger than that of silicon, which is the primary material of the electronic devices under test 4. Therefore, during the electrical testing in a higher or a lower temperature, the deformation of the guide plate, especially the deformation of the bottom guide plate, is larger than the deformation of the electronic devices under test 4 due to the difference between the thermal expansions of the different materials. And this indirectly leads to the offset of the probe pins 3, and thus causing the probe pins 3 to not align with the electronic devices under test 4.
In another known conventional vertical probe card, the top guide plate and the bottom guide plate are made of the ceramic material. The thermal expansion coefficient of the ceramic material is similar to silicon, which is the primary material of the electronic device under test 4, so as to improve upon the disadvantageous offset of the probe pins 3 caused by the above described plastic guide plate in the higher or lower temperature testing. However, the friction coefficient of the ceramic guide plate, with especially the friction coefficient of the bottom guide plate, is larger, so that during the electrical testing of the electronic device under test 4 by using the probe card, the rubbing contact between the ceramic guide plate and the probe pins 3 leads to the forming of the powder debris, thus causing problems relating to poor probe pin mobility and stuck probe pin. Therefore, the guide plate made of ceramic material leave something more to be desired.